/**
* Tests if the Model contains the given statement.
* TRUE if the statement belongs to the model;
* FALSE otherwise.
* Expects a statement of ResResources(ResLiterals)
*
* @param object Statement $statement
* @return boolean
* @access public
*/
function contains(&$statement)
{
return $this->model->contains(new Statement($this->_resNode2Node($statement->getSubject()), $this->_resNode2Node($statement->getPredicate()), $this->_resNode2Node($statement->getObject())));
}